Route your belts freely underground.
Mods introducing new content into the game.
Augmented or new ways of transporting materials - belts, inserters, pipes!
I am unable to place Underground Belt ghosts on the belt layer
save: https://drive.google.com/file/d/1JKaDsKqYK4i0I9Ka_7-RU3zlRylmGJUx/view?usp=sharing
addendum: not only this but it seems that I cannot place any underground belt using a blueprint
Thanks for the report on underground belt ghosts not being placeable underground. I have fixed this and it will be released in the next version.